I schedule each day down to the hour, but I don't paint myself into a corner. It's easy to do it, and I did it for many months. I would sit down each night, pull out my list of tasks for the next day, and them plan them out. I would start the first tasks at 8am and then keep adding them, hour by hour, until my final task ended at 5pm.
What I experienced those months was constant frustration and disappointment. I would never get everything done that I had planned. That would compound into my lead-time on new projects. And that, in turn, would impact my monthly income potential. It sucked, but I wasn't aware it was my fault for a very long time.
Then I started to end my schedule of tasks an hour earlier than my day was scheduled to end. If I had to leave the office at 4pm that day, my list of tasks was only mapped out until 3pm. There was always a buffer in my schedule.
Now, you might be thinking this was inefficient, but you're wrong for a few reasons. First, it gave me the freedom to answer small emails that drift in throughout the day, giving my clients a quicker service than they would be expecting. Those emails will need my time anyway, and so rather than saving them for tomorrow, I do them immediately.
This also allows me to finish my day with a better chance of having completed everything I hoped. That's encouraging and really fills my tank for the next day. I feel like a champion when all the boxes on my list have checkmarks in them.
Lastly, I'm better able to gauge when I will have time to start new projects. That lets me help clients out faster, and help more of them each month. If you've been doing this for even a little while, you know that's a good thing.
Working within a buffer will improve everything. Your mood and your business will get a kick in the pants. It sounds counterintuitive, but it's something I've seen work over and over, month after month.
Go. Build a buffer.